A medical ventilator delivers gas to a patient's respiratory tract and is often required when the patient is unable to maintain adequate ventilation. Known ventilators typically include a pneumatic system that delivers and extracts gas pressure, flow and volume characteristics to the patient and a control system (typically consisting of knobs, dials and switches) that provides an interface to a treating clinician. Optimal support of the patient's breathing requires adjustment by the clinician of the pressure, flow, and volume of the delivered gas as the condition of the patient changes. Such adjustments, although highly desirable, are difficult to implement with known ventilators as the ventilator demands continuous attention and interaction from the clinician.
On the other hand, recruitment maneuvers require the lungs to reach elevated peak pressures generally about 40 cm H2O. As the lung compliance increases during lung recruitment, it is possible to put large volumes of respiratory as into the lungs, potentially hyperventilating the patient. Excessive washout of CO2 (commonly referred as Hypocapnea) alters blood acidity, which can drastically increase systemic vascular resistance, cardiac arrhythmias, and can lead to severe adverse hemodynamic reactions. Hypocapnea is also associated with bronchoconstrictions, bronchospasms and increased airway resistances.
In order to achieve a more consistent level of CO2 elimination during recruitment, the volume of respiratory gas delivered into the lungs of the patient is to be controlled. This can be achieved by breath-to-breath adjustment of one of the peak inspiratory pressure and the PEEP. In practice, this cannot be achieved manually.
In order to achieve a consistent level of CO2 elimination, one of the prior arts describes a volume controlled ventilation mode, where the inspiratory pressure is adjusted to maintain a set tidal volume.
In another prior art, the clinician manually tries to titrate PEEP, as an alternative to varying the peak inspiratory pressure, to maintain a set tidal volume.
Hence there exists a need to provide a ventilator, which is easy to operate and can also provide increased safety and reliability for the patients.